Shock mitigating nose



Nov. 12, 1963 s. E. WEST SHOCK MITIGATING NOSE Filed Feb. 2, 1962 2 Sheets-Sheet 1 INVENTOR. STANLEY E. WEST ATTY.

Nov. 12, 1963 s. E. WEST SHOCK MITIGATING NOSE 2 Sheets-Sheet 2 Filed Feb. 2, 1962 4 ovv 2 4 2 G I F INVENTOR. STANLEY E. WEST AT TY.

United States Patent 3,1il,262 SHGCK METKGATTNG NGSE Stanley E. West, Silver Spring, Md, assignor to the United States of America as represented by the Secretary of the Navy Filed Feb. 2, 1962, Ser. No. 176,852 8 Claims. (Cl. 10254) (Granted under Title 35, US. Code (1952), see. 266) The invention described herein may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor.

The present invention relates to the field of ordnance, and .more particularly, to the use of a shock mitigating nose cone on a missile, whereby a nose cone on impact with a body of water absorbs an appreciable amount of the total energy due to the impact, and then separates itself from the body of the missile by disintegration.

In the field of ordnance, it has been the general practice to employ frangible nose cones to perform the function of separating the nose cones from the body of the missile upon impact with water. One example of such a device is seen in my copending application Serial No. 840,208, filed September 15, 1959, now Patent Number 3,048,110, under the title Frangible Nose Cone. Although such devices serve the purpose of separating the nose cone from the missile body, they have not proved entirely satisfactory under all conditions of service, especially in the subsequent retrieval of valuable scientific data and instruments from the body of the missile. Today the use of missiles for space exploration of primary importance and the success or failure of such a test is determined by the amount and reliability of the data retrieved. The instruments utilized on these flights are very accurate :and delicate as well as being costly. Frequently these instruments remain intact throughout the entire journey through space and are damaged or destroyed by the sudden change of velocity due to the space vehicle striking the Water. The problem confronting those skilled in the art was the inventing of some means to absorb some of the energy of impact so that the change of velocity is not instantaneous but is spread over a period of time.

The general purpose of this invention is to provide a new and improved nose cone for use on a high speed missile which; will enable the missile to have aerodynamic stability while in flight through the atmosphere, will absorb an appreciable amount of the total energy of impact of the missile with a body of water so that r the instruments within the missile are. not damaged, and will separate from the missile as it enters the body of water so that the blunt, fiat nose of the missile body will enable the missile to be stable within the water. For the missiles flight in air a sharp cone on the missile is desirable in order to have aerodynamic stability. When the missile enters the water it is desirable to have a blunt nose for greater stability while traveling in the Water. The present invention accomplished this general purpose by having a tapered nose cone, closed at one end and open on the other end with the open end attached to the main missile body portion for its flight through the atmosphere. This nose cone is made of a hollow plastic shell with the inside filled with shock mitigating means such as lead buckshot, glass beads or plastic foam or any other energy absorbing means suitable for the purpose. Upon impact with a body of water the nose cone breaks and the shock mitigating means absorbs an appreciable amount of the total energy of impact and then the entire assembly of the nose cone including the shock mitigating means is detached from the missile ice body so that the blunt nose of the main missile body portion is effective for its travel through the water.

An object of the present invention is to provide a new and improved missile nose cone that will have stable aerodynamic characteristics.

Another object of the present invention is to provide a new and improved missile cone which will be completely destroyed upon impact with another object.

Still another object is to provide a missile nose cone that will mitigate the shock of impact with an object.

A further object of the present invention is to provide protection for the delicate apparatus within the missile body as the body strikes a target surface.

Other objects and many of the attendant advantages of this invention will be readily appreciated as the invention becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings wherein:

FIG. 1 is a plan view of the invention;

FIG. 2 is an enlarged diagrammatic view partially broken away of one embodiment of the present invention;

Fit 3 is a diagrammatic View of another embodiment of the present invention;

FIG. 4 is a view of the device somewhat reduced and taken along the line 4-4 of FIG. 2;

FIG. 5 is a view of the device taken along the line 5-5 of FIG. 3; and

FIG. 6 is a section of the device taken along the line 66 of FIG. 2.

Referring now to the drawings, wherein like reference characters designate like or corresponding parts throughout the several views, there is shown in FIG. 1 the main body or" the missile 12 with its fiat nose in the front 13 to which is attached nose cone 111. This figure shows the missile with its angle of approach toward a body of water. The angle of entry of the missile into the Water in FIG. 1, is only illustrative and may range from vertical to nearly horizontal.

FIG. 2 is an enlarged sectional view of the nose cone ll of FIG. 1 which shows the hollow plastic shell to of the nose cone attached to main portion 12 by shearable screws 17. Within the plastic shell 16 there is a bowlshaped member l8 made of brass. This bowl-shaped member 18 abut-s with the plastic shell 16 by a suitable step 29 molded into the plastic shell 16. This cup 18 is so designed so that the force exerted on the cone 16 when the missile strikes the water is transmitted through the cone by way of step 26 to the brass bowl-like member 13. This brass bowl-like member 13 divides the space Within the plastic cone into two portions or volumes. One portion is bounded by the inside of plastic cone in and the inside of bowl-sl aped member 18. The second portion is bounded by the outside of bowlashaped member 18, plastic cone l6 and the main body 12. of the missile. The volume bounded by the inside of the cup is and the plastic cone to is filled with balllike members 21 which are composed of any suitable shock material such as lead, buckshot or glass beads or any such material which is capable of absorbing kinetic energy. The second portion of the space bounded by the outside of bowl-shaped member 18, the inside of plastic cone to and the outside of missile body 12 is filled with a second shock absorbing plastic foam 24 having a density of approximately 30 pounds per square foot. This plastic foam 24 has a plurality of slots 2-5 out partially through the material. This is shown better in FIG. 4 and will be described in greater detail. The screw 19 arrangement is provided for filling the cone 16 with the ball-sha ed members 21.

In o eration, lastic cone is resents an aerod nami .r' l P cally smooth surface for the missile traveling through space or the atmosphere, as the case may be. Upon impact with the water, FIG. 1, a force of impact is applied to the plastic shell 16. This force of impact is transmitted through the plastic shell 16 to the ball-shaped members 21 since the plastic shell 16 is frangible. The ballshaped members comprising lead, glass beads or any other suitable material which can absorb the energy of the shock are compressed together and produce heat. Due to the fact that there are very many of these small balls a certain amount of friction in between the balls associated with each other is produced which absorbs a portion of the energy of the impact. In actual tests, the force of the impact on the missile body portion has been reduced from 2500 gs to 1200 gs. The force applied to plastic cone 16 is also transmitted through the plastic cone to the step 20 which is an integral part of the plastic cone. This force pressing on the step then is transmitted to brass bowl-like member 18 which is also destroyed or broken by the impact of the missile with the water. The screws 17 attaching the plastic cone to the missile are sheared oif due to the force applied to the side of the screws by the plastic cone 16. These screws also absorb a portion of the energy as the missile continues in its flight. The plastic cone hitting the water is slowed or impeded and a force tending to push the plastic cone back on the body 12 of the missile compresses the plastic foam 24. The slots 26, FIG. 4, cut into the plastic foam 24 insure that the plastic will serrate or break into pieces and become free of missile body 12. The traveling of the plastic cone back upon the body 12, FIG. 1, of the missile also applies a force in circumferential tension around the plastic cone 16 which tends to break the plastic cone toward the rear open-like portion thereof due to the wedge action produced by the body 12. Thus the force of impact applies a pressure to the hollow frangible nose cone or plastic shell 16 which is of circular cross section with the open end facing or attached to the main body of the missile 12 and the closed end or nose portion is the end which first strikes the water. This force is transmitted to the screws 17, which are sheared, and to the plastic foam 24, which is serrated along the slots 26. The greater portion of the force is transmitted to the shock mitigating means 21 which, in conjunction with the force applied on the steps 20 of the plastic shell 16, break the bowl-shaped member 18. The grooves 15, shown also in FIG. 6, cut into member 18 insure that the member 18 will break and free itself from the missile body upon impact with the water. Upon destruction of the plastic cone, the brass bowl-shaped member 18 and the foam, these members are separated from the mainnon-frangible missile body 12 so that the main missile body now has a flat blunt nose 13, FIG. 1, to retard its movement as it travels through the water. This flat nose body of the missile 12 is stable while traveling through the water.

FIG. 3 shows another embodiment of the present invention in which like reference numerals apply to like members as shown in FIG. 2. The embodiment of FIG. 3 comprises only changes in the bowl-like member 18. The bowl-shaped member 18 of FIG. 3 is composed of lead with a magnesium plate or shield 27 encircling the lead. Four slots 22, also shown in FIG. 5, are cut into the side of the bowl-shaped member 18 and are shown as the non-hatched portion in FIG. 3 and shown also in FIG. 5. Magnesium ring 27 has a platform 32 upon which step 20 of plastic shell 16 rests. The operation of the embodiment of FIG. 3 is similar to that of FIG. 2 in that the force of impact of the plastic cone 16 upon contact with the water transmits the force to ballshaped members 21 which interact among each other and are compressed and transmit the force to the bowl-shaped member 18 so that an outward force is applied to the member 18. Slots 22 in the sides allow this bowl-shaped portion to separate and disintegrate since the slots cut into the side are placed there so that a weak portion is present in the body. The outward force on member 18 causes the magnesium ring 27 to burst from circumferential tension. The inter-action of the cone 16 with the plastic foam 24 is as described in FIG. 2.

FIG. 4 is a sectional view of FIG. 2 taken along the line 4--l. In FIG. 4 the main body portion 12 is shown with the plastic foam 24 encircling the main body portion. Slots 26 are cut into the plastic foam in order to insure that the plastic foam will serrate. Encircling the plastic foam 24 is the plastic nose cone 16.

FIG. 5 is a sectional view of FIG. 3 taken along the line 55 thereof. This section shows, proceeding from the outside to the inside, the plastic cone 16, the plastic foam 24, the magnesium ring 27, and the bowl-shaped member 18 with the unhatched portion 22 indicating the slots cut into member 18 in order to insure that it will separate from the missile upon impact.

FIG. 6 is a sectional view of FIG. 2 taken along the line 6-6 thereof. This section shows, proceeding from the outside to the inside, the plastic cone 16, the plastic foam 24, the bowl-shaped member 18 with V-shaped grooves 15 cut into member 18 and the unhatched portion shows the inside of bowl-shaped member 18 partially filled with shock mitigating means 21 for the purpose of illustration. The grooves 15 are cut into member 18 to insure that this member will separate from the missile body upon impact with an object.

As has been pointed out in the detailed description of the drawings a new and useful invention has been disclosed. It has been shown that the novel cone of the invention with the shock absorbing material filling the cone absorbs an appreciable amount of energy of impact of the missile with the water. The inter-action of these ball-shaped members among each other has been shown by experimental tests to reduce the shock of impact from 2500 gs to 1200 gs. This invention is useful with missiles which carry delicate instruments in that the shock of impact has been reduced by more than 50%.

Various modifications are contemplated and may obviously be resorted to by those skilled in the art, after understanding the invention, without departing from the spirit and scope of the invention, as hereinafter defined by the appended claims as only the preferred embodiments thereof have been disclosed.

What is claimed as new and desired to be secured by Letters Patent of the United States is:

1. A shock absorbing device comprising, a non-frangible missile body portion, a hollow frangible nose cone connected to said body, a frangible bowl-shaped device connected to said body and to the inside of said cone dividing the space in said cone into two portions, a first shock mitigating means comprising a plastic foam filling one portion of said space bounded by said body, said cone and said bowl-shaped member cup, a second shock mitigating means comprising a plurality of ball-shaped objects filling the second portion of said space bounded by said cone and said cup, whereby an appreciable portion of the total energy produced upon the impact of said device with an object is absorbed by both of said shock mitigating means and in the destruction of said cone and said bowl-shaped device.

2. A device as recited in claim 1 wherein the ballshaped objects of second shock absorbing means comprise lead.

3. A device as recited in claim 1 wherein the ballshaped objects of said second shock absorbing means are composed of glass.

4. A device as recited in claim 1 wherein shearable screws connect said cone to said body.

5. A shock mitigating frangible nose cone for use on a missile comprising a main missile body portion, a hollow plastic shell nose cone of circular cross section with one end open and the other end closed and attached to said missile body, a plurality of screws attaching said nose 5 cone to said body in such manner that upon impact of the missile with water said screws are sheared, a frangible bowl-shaped device connected to said nose cone and to said missile body in such manner that the space inside said nose cone is divided into two portions, a first shock mitigating means comprising ball-shaped objects filling.

one portion of the space bounded by said cone and said cup, a second shock mitigating means comprising a plastic foam filling the other portion of said cone bounded by said missile body, said cone and said cup, a plurality of slots in said plastic foam whereby said foam is serrated along the slots upon impact, so that upon impact of the missile with a body of water an appreciable amount of the total energy of impact is dissipated in the compression of said first and second mitigating means and in the destruction of said plastic cone, said bowl and the shearing of said screws.

6. A device as recited in claim 5 including a first step 5 formed on the inside of said plastic cone for engaging said bowl whereby the force of impact is transmitted from said cone to said bowl.

7. A device as recited in claim -6 wherein the ballshaped objects of said first shock mitigating means are composed of lead.

8. A device as recited in claim 6 wherein the ballshaped objects of said first shock mitigating means are glass beads.

References Cited in the file of this patent UNITED STATES PATENTS 1,283,075 Chacon Oct. 29, 1918 1,298,085 Nikonow Mar. 25, 1919- 2,732,040 De Vost et a1. Jan. 24, 1956 2,942,545 Fogal et al. June 28, 1960 2,947,255 K-uck et a1. Aug. 2, 1960 3,048,110 West Aug. 7, 1962 

1. A SHOCK ABSORBING DEVICE COMPRISING, A NON-FRANGIBLE MISSILE BODY PORTION, A HOLLOW FRANGIBLE NOSE CONE CONNECTED TO SAID BODY, A FRANGIBLE BOWL-SHAPED DEVICE CONNECTED TO SAID BODY AND TO THE INSIDE OF SAID CONE DIVIDING THE SPACE IN SAID CONE INTO TWO PORTIONS, A FIRST SHOCK MITIGATING MEANS COMPRISING A PLASTIC FOAM FILLING ONE PORTION OF SAID SPACE BOUNDED BY SAID BODY, SAID CONE AND SAID BOWL-SHAPED MEMBER CUP, A SECOND SHOCK MITIGATING MEANS COMPRISING A PLURALITY OF BALL-SHAPED OBJECTS FILLING THE SECOND PORTION OF SAID SPACE BOUNDED BY SAID CONE AND SAID CUP, WHEREBY AN APPRECIABLE PORTION OF THE TOTAL ENERGY PRODUCED UPON THE IMPACT OF SAID DEVICE WITH AN OBJECT IS ABSORBED BY BOTH OF SAID SHOCK MITIGATING MEANS AND IN THE DESTRUCTION OF SAID CONE AND SAID BOWL-SHAPED DEVICE. 